Wastewater Treatment, Pretreatment, and Hauled Waste

Industrial Pretreatment

Management of significant industrial users (SIUs) has been an important part of wastewater treatment plant operations since the 1980s, when new plants began experiencing process upsets due to industrial discharges. LRWWU has had an EPA-approved Industrial Pretreatment Program (IPP) since 1998. The purpose of the IPP is to prevent pass-through and interference caused by industrial discharges.

LRWWU's diligence with pretreatment activities can be credited for its success in avoiding process upsets and non-compliant discharges to the Merrimack River. Over the years, the number of SIUs has declined slightly, as domestic manufacturing has moved overseas. Recently, LRWWU began focusing on monitoring hauled waste discharges at the Duck Island WWTF, particularly industrial hauled waste. LRWWU plans to increase its monitoring of domestic and commercial septage once a new electronic billing system is implemented in 2015. This monitoring of hauled waste and management of its billing is crucial to prevent interference or pass-through of harmful pollutant loads.

Supervisory Control and Data Acquisition / Process Control

LRWWU engineers have an important role in managing the operations of the Duck Island WWTF through the Supervisory Control and Data Acquisition (SCADA) System. Most of the processes in the Duck Island facility are controlled remotely through SCADA, which is a state-of-the-art distributed control system. SCADA's maintenance and troubleshooting is overseen by the Engineering Supervisor. In addition to overseeing the SCADA system, LRWWU engineers also work closely with the Operations Division to ensure that the treatment processes are operating smoothly and providing effective treatment. A particularly important aspect of process control is the monitoring and troubleshooting of odors that may be generated throughout the wastewater treatment process.